Telephone system



March 10, 1931. R. DAHMS 1,795,295

TELEPHONE SYSTEM Filed' May 14, 1930 2 sheets-shed 1 Naw.

March l0, 193i. R.v Din-mls TELEPHONE SYSTEM 2 Sheets-Sheet 2 Filed May 14, 1930 VLZ , rlp?" l VLI Paterted ltilar. l0, 1931 insges :RUDOLF DARES, F BERIN, GERMANY, ASSIGNGB TU SIEMENS & EALSKE .A 'KTEN- GESELLSCHAFT, 0F WERNERWERK SIEMENSSTADT, NEAR BERLHQ', GERMANY TELEPHONE svsfrnrr application med May 14, 1930, Serial No. 452,41?, and in Germany May t, 1929..

'llhe invention relates to a circuit arrangement for automatic telephone systems, in which lines of different length are-connected together over selecting devices. lt'is known l that the long lines have a greater damping together.

than the short ones, so it is necessary to insert ampliers in the connections set up over long lines, while the insertion of amplifiers is not required when shorter lines are connected Now the object of the invention is to effeet in an entirely automatic and suitable manner the switching in of the ampliers in those cases where this insertion of amplifiers is necessary; and according to the insitloned, switching means come into action that determine, according to the incoming -and outgoing lines, whether an amplifier is to be inserted in the interconnected lines or Whether the lines remain interconnected without the insertion of an amplifier.

Three methods of carrying out the invention are hereafter described and shown in the drawing. 4

Fig. l shows a method of carrying out the invention whereby a telephone station over an incoming line from a distant exchange sets up a connection automatically to another telephone station, which is also connected to a long line, this being done by means of an impulse sender. After the connection has been set up, the ampliiers are switched in, this being done over a special by-path, over which subsequently the speaking connection extends, while the connecting route over the various selecting stages for setting up the connection is entirely disconnected after the amplifier has been switched in. lThe circumventing of the switches over which' the connection is set up has the advantage that a reduced number of group selectors can be provided, because they are used only during the comparatively short time occupied in setting up the connection and they are re- ,k leased as soon as the amplifier has been switched in.

Fig. 2 shows another method of carrying out the invention wherein the amplifiers are switched into the connecting route, for example between the selecting stages, the connecting route being opened after the ampliers have been switched in.

lig. 3 shows an arrangement similar to Fig. 2, but here the ainpliers are directly switched onto the connection, in the example shown they are switched onto the incoming junction line. bviously the connecting up could also be eiiected at the outgoing line. Here also the connecting route is opened after the connection has been set up.

The method of setting up a connection will frst be described with reference to the arrangement shown in llig. 1. lt will be assumed that a telephone station making a call overthe junction line VL 1 incoming from a distant exchange wishes to set up a connec-` tion with a telephone station that can be reached over the junction line VL 2, which may extend over other exchanges.- rlhe junction lines VL l and VL 2 are long junction x lines requiring an amplifier to be switched in when' they are interconnected. In the present case it is assumed that the exchanges located in the connecting route'are automatic exchanges whereby the subscribers can set up a connection without the assistance of a trunk operator. l

When the calling station initates a call over the incoming line VL 1, the relay C 1 associated with the incoming line VL l in hewn manner is energized over: earth, battery, winding of relay C l, contact 20 u 1, lead c and earth at the preceding exchange. Relay C 1 operates its contacts.V rThe incoming current impulses energize the relay J located in the incoming junction line and in accordance with the impulses its contact 2 'j a lies earth to the a lead of the junction line ga 1, thereby the relay A 1, which likewise is connected to the a lead, is energized at each impulse in the circuit over: earth, battery, Winding of relay A 1, contact 9 fw, lead a, contacts 21 u 1, 2 j, earth. Each time relay A1 is operated its contact 3 a 1 is closed, whereby the liftin magnet H of the first group selector I. W is energized over earth and' contact 4 fw, the relay P 1 being energized in arallel therewith over its winding III. l agnet II raises the wipers of the switch to the desired level and relay P 1 short circuits its winding I over its contact 10 p 1. This short circuit of its winding I causes the relay P 1 to remain energized during the impulse transmission. Cn falling back at the end of the impulse train the relay A 1 opens the circuit of the liftin magnet H and of relay P 1, hence over the o -normal contact 22 7c, which was closed at the first lifting step, the now closed contacts 6 p 1, 5 a 1, and 23 c 1, the ro tary magnet D of the switch is connected up and sets its wipers in motion. At the first rotary step the contact 8 d is closed and 9 w is opened, and the switch is moved on step by step in known manner by the interaction of of the rotary magnet D and the relay A 1, which operate as a relay interrupter. During this time the opened contact 9 w disconnects relay A 1 from the lead a.

When the wipers of the switch IGW have reached the contact of a free switch in the'next switching stage, for example a free II.GW, the relay P 1 is again operated over earth, contact 1 c 1, winding I and II of relay P 1, switch wiper and battery at the succeeding switch; by closing its contact 10 p 1 it short circuits its winding I, thus the seized switch II.GWis marked engaged to other calls. The junction line VL 1 has now been connected to the v switch ILGW over the closed contacts 11, 12 and 13 p l. The selections over the selecting stages II and III GW take place in the same manner as described before, which is known per se. When the last switch in the selecting stage III.GW has been positioned on the line VL 2 going in the desired direction, the seizing relay C 2 is energized over its winding I associated with the outgoing end of the junction line VL 2; by closing its contact 54 c 2 it seizes at the terminal exchange of the outvoin line VL 2 a switch for selecting the sulbscrlber or an outgoing junction line.

After the connection has been established over the switches I, II and IIIGlV, the relay K at the incoming end of the junction line VL 1 is operated at the same time and closes its contact 14 c, thereby operating at the call distributor AO the relay R 1 over: earth, contacts 14 c, 15 p 3, winding of relay R 1, battery, earth. At its contact 16 1` 1 the relay R 1 closes the circuit for the rotary magnet D 1 of the assignor over: earth, contacts 17 p 3, 16 1' 1, winding of D 1, battery, earth. The step-by-step movement of the switch is effected in known manner by the rotary magnet D l operating alternately with the relay R 1, so that the call assigner AO takes a step each time the circuit of D 1 is closed; after each step the relay R 1 is short circuitedvover the closed contact 18 d 1 and at contact 16 1 1 it opens the circuit of the rotary magnet.

meaaea Contact 18 d 1 isv opened again, relay R 1 is again operated and contact 16 1 1 again closes the circuit of D 1.

When the wiper of the call assignor AO has reached the lead going to the fourth wiper of the first group selector, the relays P 3, B 1 and-B 2 are simultaneously operated in a circuit over: earth, winding of relay P 3, switch wiper, relay 1, contact 19 u 1, key 'I'a l, contact 13 79 1, the switches at-each selecting stage I, II and III GlV, key Ta 2, winding of relay B 2, battery, earth. These relays operate their contacts. Relay P 3 at its contact 17 p 3 opens the circuit of the rotary magnet D 1, which is arrested and at contact 15 p 3 it opens the circuit of relay R 1, which opens its contact 16 1' 1.

Relay P 3 at the same time over contact 24. p 3 closes the circuit of relay R2 at the amplifier distributor VV. The amplifier dis tributor VV is always standing on a free amplier set, which is designated by the contact 55 a being in its normal position.

In its normal position contact 25 t is closed and 56 t is open.' Relay T is energized over its winding II and contact 55 2hence in the operating position contact 25 t is open and 56 t is closed.

Therefore when contact 24 p 3 is closed, the relay R 2 is operated and preparatorily closes its contacts 27 and 28 1 2 as well as D 3 and D 4, which at their contacts 29 d 3 and 30 d 4 alternately short circuit relay R 2, while relay R 2 at its contact 29 1 2 alternately closes and opens the circuit of the rotary magnets.

lVhen the wipers of the switches AW 1 and AW 2 reach the contacts of the calling and called lines, the relays P 4, U 1 belonging to the calling line VL 1 and the relays P 5, U 2, C 2 winding II belonging to the outgoing line VL 2 are operated in the following circuit: earth, contact 27 1a 2, relay P 4 windings I and II, switch wiper, contacts 31 c 4, 346 1, winding of relay U 1, battery, earth; as well as: earth, contacts 28 1 2, 57 e, windings I and II of relay P 5, switch wiper, contact 35 b 2, winding of relay U 2, winding II of relay C 2, battery, earth. The relays P 4 and P 5 at their contacts 58 p 4 and 59 p 5 open the circuits of the rotary magnets D 3 and D4 of .the amplifier selectors AWV l and AW 2, so that the latter are arrested. At the same time are closed the contacts 60 p 4,- 53 p 4 and 36 p 5 in the circuits of the relays U 1, P 4,

lll

I U2 and15aswellasthecontacts32p4and 5 and Contact 73 p 5 is opened.- Over the contacts 32 p 4 and 78 p 5 the relay Z is operated and actuates its contacts. Over the contacts path connected -to the calling and the outgoing junction lines VL 1 and VL 2. The .windings II and I of relays P 4 and P 5, respectively, are short circuited over the closed contributor VV and the interaction of the rotary magnet D 2 and relay T then moves the switch VV to the next free amplifier in lmown manover the contacts 65, 66 and 49 u 1 to the calling junction line VL 11 and over the contacts 67, 68 u 2 and 50 u 2 tolthe outgoing junction line VL 2. Contact 20W 1 connects the relay C 4 in place of relay G 1 to 'the lead c of the calling line.

The connecting up of the ley-path to the junction lines VL 1 and VL 2 and the simultaneous opening of the contacts 45, 46 and 21 u l and 47 and I48 u 2 caused the connecting route set u over the selecting stages L ll. and IlIGr to be disconnected and j released, and the speaking route now entends over inserted amplilier andy the leads of the by-path connecting the amplifier to the lines VL 1 and VL 2. Contact 54 c 2 is kept closed in the e lead of the junction line VL 2, he-

cause after the opening of contact 7 0 u 2 has (le-energized winding 1 of relay C 2 the latter is held over its winding l1 located in the circuit of the relays P 5 and Il 2. 0n being operated, the relay U lat contact 19 u 1 opens the circuit of the relaysK, P 3, B 1 and B 2, and they fallback. Relays B 1 and B 2 open their .contacts 34 b 1 and 35 5 2 in the circuit of relays U 1, P 4, Il 2 and P 5, which are held over the contacts 71 u 1 and 31 c 4 and 32 u 2 that have been closed 1n the meantime. Relay P 3 closes its contacts 15 p 3 and 17 p 3.and the call assignor AO is lnow free for other calls.

As soon as the calling station now transmits the other impulses for reaching 'the wanted subscriber, the relay J, which lies in the incoming junction line VL 1, receives impulses, at each of which its contact 2 j applies earth to the lead a. rllhe impulses now go over the third lead of the bypath and energize the relay A 2 in -the outgoing junction 61, 37, 38, 39, 40, 4 1, 42', 43 and 44 z. the amplifier is switched into a. separate by-v 'Uland lcuit ol the fourth switch wiper. these keys opens the circuit over the fourth j line over: earth, contacts 2 y', 49 lu 1, n

switch lAW 1, contact 61 z, wiper of switch AW 2, contact 50 u 2, lead a, choking coil 1 DR I, relay A 2, battery, earth. Relay A 2 repeats the impulses b closing its contacts 51 a 2 and 52 a 2, thereli'y applying the alternating VL 2; lThis further selection can be effected satisfactorily'in eve case, that is to say also when for example t erelaysA U 1 and 'U 2 have not yet been energized or their contacts place either over the contacts of the relays U 2, which are still connected to the a lead or over their contacts already connected to the third lead of the hy-path.

At the end ot the conversation when the cal-ling subscriber hangs up his receiver, the relay C 4 at the incoming end of the junction vline VL 1 is rie-energized and at contact 31 c 4 it opens the circuit o: the relays U 1 and P 4, whereupon these relays fall back. Over the contact 53 p 4 the circuit of the relays P 5 and 2 and winding 1I of relay C 2 is also opened, thereby releasing the connection. Relay Z is energized untily the relays P 4 and P 5 have fallen hack and its winding is short circuited at contact 73 p 5. 'llhe release of the switches inthe preceding distant exchange was also initiated when the relay C 4 belonging to the incoming junction line VL 1 fell hack.. v

For certain reasonsit will not always he necessary to use ampliers 'lor connections current source to the junction line are in the act of being switched over. In that condition the impulse transmission takes over long lines. To provide for this two ke s To 1 and To; 2 are inserted in the cir- Pressing switch wipers and relay K, hence this relay and likewise 'the relayslP 3, B 1 and B 2 can not loe operated and the ampliliers thereforeI are not connected up.

In the foregoing it hasheen described that the designation lfior the connecting up of the amplifiers takes place over the relay K located in the circuit of the fourth switch wiper. This designation can also 'be so arranged that for example the fourth switch wiper is omitted. rlhe connecting up oi the relays K, B 1 and B 2 then takes place over the lead of the setting up route as is shown dotted in the Fig. 1 ot the drawing. The circuit `of relay K then extends from .earth over the winding ot the relay K, contact 19 u 1, key Ta 1, contact 13 p 1, choking coil 1I Dr, lead l), switch, lead, choking coil II D1' 1, key

T02, winding oi relay B 2, battery, earth.

When the station calling over theA incoming line VL 1 sets up a connection to a station accessible over the short line VL 4, the connection is set up over the selecting stages I, II and HIGVV in the same manner as previously described. The line VL 4 being a short line, it is not necessary to insert an amplifier when such a line is connected to the line VL 1, and, therefore, the line VL 4 does not have the means :for connecting up amplifiers, for example the relay B 2. Hence no amplifier can be inserted, because the absence of this means at this line also prevents the means at the calling line (relay K,B 1) being operated. The lines remain connected together over vthe route, that is to say over the switches,

-used for setting up the connection; thus this connecting route also forms l the speaking route.

The same applies to the interconnecting of two short lines, for example VL 3 and VL 4. rlhe connection is set up in the same manner as that previously described. As none of these lines have the means (relays K, B 1 and B 2) for connecting up the amplifiers, the latter cannot be inserted. The speaking route extends over the setting route, that is to say over the switches.

In the example according to F ig. 2 it will be assumed again that a station calling over the junction line VL 1 sets up a connection to a station that can be reached over the line VL 2. Contrary to the example according to Fig. 1, the insertion of the amplifier, in-

stead of being inserted over a special by-path,

is directly inserted in the connecting route, namely between two selecting stages, which are assumed to be the first and second group selectors I. and ILGW.

When the connection has been set up over the different selecting stages in a manner similar to that described in the first example, the relay A belonging for example to the first group selector and the relay B belonging to the second group selector are operated. At

their contacts 101 a and 102 b they close al circuit for the relay C. The latter actuates its contacts 103 c to 108 c, thus connectin up the amplifier V. The contacts 103, 104 and 105 c at the same time disconnect the connecting route. The speaking route extends over the amplifier and the selecting stages located in front and beyond it, that is to `say over the setting route and the inserted amplifier.

In this example when the station calling over the incomingr line VL 1 sets up a connection to a station that can be reached over the short line VL4, no amplifier is inserted, because the means, i. e. t e relay B is missing from it. The circuit of relay C remains open, the connecting up of an amplifier is prevented.

the amplifiers in the example 3 are directly connected to the lines as shown for example to the incoming line VL 1. Obviously the tacts 121 a to 126 a connects the amplifier to the incoming line VL 1 and at the same time the operated contacts 121, 122 and 123 a open the connecting route. The speaking route extends over the amplifier and the different selecting stages.

What is claimed is:

1. In a telephone system, an incoming line, an outgoing line, automatic switches controlled over said incoming line for interconnecting said lines, an amplifying device, and means responsive to said interconnection for directly connecting said lines through said amplifying device and forreleasing said auto! matic switches.

2. In a telephone system, an incoming line, a plurality of outgoing lines of two classes, a train of automatic switches controlled over said incoming line to select anyone of said outgoing lines, an amplifying device, and means effective only if the selected line is of a particular class for substituting said amplifying device for said train of automatic switches. i

3. In a telephone system, a plurality of incoming lines divided into two classes, an outgoing line, a train of automatic switches controlled over a calling incoming line to connect withl said outgoing line, an amplifying device, and means veffective only if said calling line is of a particular class for substituting said amplifying device for said train of automatic switches.

4. In a telephone'system, an incoming line, a plurality of outgoing 'lines divided into two classes, automatic switches controlled over said incoming line for selecting any one of said outgoing lines, an amplifying device, and means effective if the selected line is of a particular class for inserting said amplifying device in the connection between the incoming and theselected outgoing line.

.5. In a telephone system, j a plurality of incoming and outgoing lines, means controlled over a calling incoming line for connecting the line to one of said outgoing lines, discriminating means associated with certain of said lines having predetermined characteristics, a repeater, and means controlled by said discriminating means and effective only if both of said interconnected lines are of groenen said characteristics for automatically including said repeater in said connection. p 16,. in a telephone system, a plurality of incoming and outgoing lines divided into two classes, a train of automatic switches operated 4 over a calling incoming line to connect with one ci' said outgoing lines, a plurality of common link circuits each comprising a repeater and two inders, means eiective only if "ihoth' of the connected lines are of a particular class for associating an idle link circuit with said connection, and means for operating said K two ndere to connect with the incoming and the outgoing line, respectively, thereby coml5 pleting said connection through said repeatera 7. lin a telephone system, a plurality of incoming and outgoing lines divided into two classes, a train of automatic switches operated over a calling incoming line to connect with one ci said outgoing lines, a plurality of common linlr circuits each comprising a reeater and two nders, means effective only if oth of the connected lines are of a particular class for associating an idle link circuit with said connection, means for operating said two nders to connect with the incoming and the 'outgoing line, respectively, thereby completin said connection through lsaid repeater,

an means for thereafter releasing said train oitautomatic switches.

8 ln a telephone system, a plurality ci incoming and outgoing lines divided into two classes, automatic switches controlled over a calling incoming line to connect with one oi said outgoing lines, a plurality oi common link circuits each including a repeater, andv means operative only if both'of the connected lines are of a particular class lfor-replacing 4o said automatic switches with antidle one o `said link circuits to connect said lines.

9., in a ltelephone system, a plurality oi lines, automatic switc es controlled over a calling line for connecting said line to a de .is sired called line, a plurality of common re1 peeters, and means responsive to said connec tion for inserting an idle one of said repeaters in the connection between the calling and called lines,

1G., ln a telephone system, a plurality ci lines, automatic switches controlled over a calling line for connecting said line to a de= sired called line, a plurality of common re peaters, and means responsive to said con nection for connecting the calling and called lines through an idle one of said repeaters and or'rele'asing said automatic switches.

ln witness whereof, hereunto subscribe my nance this 8thV day of April, A.. D., 1930. @o RUDOLF s. 

